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Foucault, Jean Bernard Léon |
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Foucault, Jean Bernard Léon (zhäN bĕrnär` lāôN` f kō`), 1819–68, French physicist. Known especially for his research on the speed of light, he determined its velocity in air and found that its speed in water and other media diminished in proportion to the index of refraction. He originated the Foucault pendulum pendulum, a mass, called a bob, suspended from a fixed point so that it can swing in an arc determined by its momentum and the force of gravity. The length of a pendulum is the distance from the point of suspension to the center of gravity of the bob (see center of..... Click the link for more information. , with which he demonstrated the earth's rotation. He also improved astronomical instruments, especially the telescope; invented (1852) the gyroscope; and investigated the eddy current (known also as the Foucault current), an electric current induced in metal by a moving magnetic field. With Armand Fizeau he took the first clear photograph of the sun. From 1855 he was physicist at the Paris Observatory. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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